粉煤灰改良膨胀土脱湿过程裂隙发展规律与影响因素研究

Study of Cracking Characteristics and Influencing Factors for Flyash-treated Expansive Soil in Dehydration Process

环境温度、初始含水率、粉煤灰掺量和干密度均对膨胀土的幵裂有重要影响,为了分析初始含水率和粉煤灰掺量对膨胀土裂隙发展过程、发育规律、发展机制的影响进行了多组脱湿过程裂隙开展试验;并进行了定量分析。结果表明试样裂隙可分为三神:一条主裂隙加上多条次裂隙、三岔口型裂隙、环状裂隙其中掺有粉煤灰试样大多数出现第三种裂隙未掺粉煤灰的试样出现第一、二种裂隙。随着试样含水率減少脱湿过程可分为三个阶段:无裂隙阶段、裂隙产生和发展阶段、稳定阶段。裂隙度随初始含水率的增大而增大随粉煤灰掺量的增加而减小。粉煤灰掺量对未养护试样的临界含水率影响不大养护后其临界含水率增大。

The environment temperature, initial moisture content, fly ash content and dry density all have important influence on the crack of expansive soil.In order to analyze the influence of initial moisture content and flyash on fissure development process, development rules and development mechanism of expansive soil, multiple of tests is set, and a quantitative analysis is made.The results show that the crack can be classified into three： a main crack with multiple cracks, three fork type crack, ring crack, when samples mixed with fly ash most show the third crack, The first and second crack have appeared in the sample without fly ash.With the reduction of water content in the sample, the dehydration process can be divided into 3 stages： no crack stage, crack formation and development stage, stable stage.The cracking degree increases with the increase of initial water content, and decreases with the increase of fly ash content.The content of fly ash has little effect on the critical moisture content of the no curing samples, and the critical water content increases after curing.